need some expert help here- Violent shaking / pounding from engine compartment

Ok Men... here's the scoop:1999 well looked after lesabre- major violent front end shaking clunking - like the engine is 'coming apart' upon left hand turn from a stop upon hard acceleratioon- usally happens when the light is changing from a amber to red on a left hand turn in an intersection. It'll do every time. wont do it on a right hand or straight out of the gate.If I take it easy - no issue. Its so bad and startling that I immediatley withdrawl the accelerator to stop the event. Its not the tires spinning or anything like that - its as if the engine is shaking violently - unrestrained for a time. The dealer said it is likely the tranny and was thinking it muight be due to the oil pick up when the fluid shifts to the right.. Persoanlly I think thats BS and they either didnt look or dont give a @#$% as the tanny shift beauty and is only 130K with no tranny like issues. Its like something is brioke in there- also I'd say something sounds loose when I dive over a man hole cover with the left tires... Only other thing I;d mention is the car took a very hard hit on the right side a couple years ago which resulted in the lower and upper arm being replaced...I\'ve done my fair share of automotive repairs so I'm not looking for newby suggestions here... should I pull the axles, what about the engine mounts- anything???

thanks kindly
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Yes on both issues, look close at the axles and mounts, any loose suspension components including the entire subframe.

is this something a do it yourselfer can take on or ??? what do I do - pull the tires off and then start snoopin around?

My suggestion... park the car on a nice flat level surface. Engage the parking brake as firm as possible, make sure nothing is in front of your car (obstacles). Hold your left foot on the brake pedal and shift to drive. Use your right foot to feather the accelerator. If the clunking occurs, then you probably have a bad engine mount. The front motor mount is a really common one to fail first on these cars and is in tension when the car is in drive. Shift to reverse and feather the accelerator, if you feel the event then you may have a failed rear or left hand tranny mount.

The next part of my suggestion comes with a HUGE disclaimer. Take my advice at your own risk, I probably shouldn't even publicly advocate what I'm about to say. Pop the hood on the car, perform the above test using a highly trust worthy driver behind the wheel who understands the procedure. Stand off to the SIDE of the car and try to watch what happens to the motor when the person feathers the accelerator. Do not stand in the way of the tires. If you don't see the engine shifting drastically but you're still hearing the event then I would put the car up and take a serious look at the sub frame bushings and axles. Please be careful, its extremely tempting with a problem like this to try things that will get you hurt. Stand well clear of the wheels and front of the car while its in drive. Make absolultely sure the parking brake is engaged but beware that it will not restrain the car by itself even under light taps of the gas pedal. By all means do not put any part of your body in the potential path of any part of the car while its running.

Do you hear anything unusual when the car is idling in park and you cut the wheel back and forth, stop to stop? If your hearing/feeling issues while your turning the wheel back and forth then check the points where the rack and pinion mount to the frame and also the tie rods. Both failure points could cause your complaint as those components are loaded significantly during turning and acceration (due to torque steer).

I too have a '99 Lesabre that when I try to accelerate hard when at a stop and especially if I'm on a slight incline and try turning left, I will get a hard shudder comming from the front of the car. If I lay off the accelerator pedal, the shuddering stops. Took it in to the dealership and they told me it most likely is a bad Pressure Control Soleniod inside the transmission. It needs replacing and they gave me an estimate around $800-900 for the job. Mostly labor is involved. With that kind of money I decided to not accelerate hard when stopped. If problem get's worse or I have other transmission issues, I'll then get it fixed. Otherwise the car has been running fine. There's a TSB out on this issue:

A/T - 4T65E Harsh Shifts/Shudders/Slips/DTC's Set
File In Section: 07 - Transmission/Transaxle
Bulletin No.: 0O-07-30-002B
Date: July, 2002

1999 Lesabre with 105K miles, original owner.

Excellent information indeed and sounds exactly like my issue though I haven't; rulled out front end probs.. if and when I do then I suspect that what you have described is it. No other probs with the tranny- shifts beauty.
Tell me... I'm not familar with TSBs? where can I go to find this and read up?

many thanks
:
There's a TSB out on this issue:

A/T - 4T65E Harsh Shifts/Shudders/Slips/DTC's Set
File In Section: 07 - Transmission/Transaxle
Bulletin No.: 0O-07-30-002B
Date: July, 2002

What I did was goto www.alldatadiy.com/index.html (http://www.alldatadiy.com/index.html) and subcribe to a 1 year subscription for my car. If your a do-it-your-selfer or just want to know everything about your car, where stuff is located on the car, how to take things apart etc, this place will give it to you. It also lists TSB's and recalls. I found it worth the money. Unfortunetly it's not free. I think it's like $25 per car per year and like $15 for a yearly renewal or $30 for a 3 year renewal. Also you might want to try your Buick dealership and ask them what TSB's are out on you car. I can't see why they wouldn't tell you. I'm looking at AllDatadiy.com right now and I see listed over 150 TSB's for the 1999 LeSabre. I never had any luck trying to find someplace free on the internet that listed the TSB's.

Good luck.

many thanks.. good suggestion..

Incidentally, is is possible/are you prepared to cut and past the TSB you mentione din your response to me??

Greg from Langley BC, Canada..

Click Here (http://www-odi.nhtsa.dot.gov/cars/problems/tsb/tsbsearch.cfm) for TSB's

ok thanks... summary is good and better than nothing.. I'll follow up on your other advise re the pay piece for the whole backgrounder on my Lesabre
cheers
G

Here's what the TSB says:

A/T - 4T65E Harsh Shifts/Shudders/Slips/DTC's Set
File In Section: 07 - Transmission/Transaxle
Bulletin No.: 0O-07-30-002B
Date: July, 2002
TECHNICAL
Subject:
Slips, Harsh Upshift or Garage Shifts, Launch Shudders, Flares, Erratic Shifts and Intermittent Concerns, DTC P1811 or P0748 Set (Replace Pressure Control Solenoid Valve Assembly) Models:
1997-1999 Buick Riviera
1997-2002 Buick Park Avenue
1998-2002 Buick LeSabre
1999-2002 Buick Regal
2000-2002 Buick Century
2002 Buick Rendezvous
1997-2001 Chevrolet Lumina
1997-2002 Chevrolet Monte Carlo
1999-2002 Chevrolet Venture
2000-2002 Chevrolet Impala
1997-1999 Oldsmobile Eighty Eight
1997-2002 Oldsmobile Silhouette
1998-2002 Oldsmobile Intrigue
2001-2002 Oldsmobile Aurora (3.5L)
1997-2002 Pontiac Bonneville, Grand Prix
1999-2002 Pontiac Transport/Montana
2001-2002 Pontiac Aztek
with Hydra-Matic 4T65-E (RPOs MN3, MN7, M15, M76) This bulletin is being revised to add additional models and model years. Please discard Corporate Bulletin Number 00-07-30-002A (Section 07 - Transmission/Transaxle).
Condition
Some owners of the above vehicles with a HydraMatic 4T65-E transaxle may comment on harsh upshifts or harsh garage shifts, soft shifts, shudders on hard acceleration, or shifts erratic. These conditions may appear intermittently or set a DTC P1811 or P0748. During diagnosis, a low or high line pressure (actual versus desired) may be observed.
Cause
The above condition may be due to any one of the following which may affect line pressure output:
^ Sediment inside the pressure control (PC) solenoid valve, causing the PC solenoid valve to mechanically bind. ^ Sediment in the valve body, causing the torque signal regulator valve to stick. ^ Incorrect transaxle oil level. Correction
Important: Any of the above conditions may be intermittent, therefore, this test should be performed at least three times.

Refer to the Line Pressure Check Procedure in SI, along with the Line Pressure Specification Table shown, to determine if actual versus desired pressures are within the values specified. The Scan Tool is only able to control the PC solenoid valve in PARK and NEUTRAL with the vehicle stopped. This protects the clutches from extremely high or low pressures in DRIVE or REVERSE ranges.
Refer to the Line Pressure Specification Table. The pressures in the table assume a temperature of 70°C. The pressure will vary with a change in temperature.
If the actual versus desired pressures are not within the values specified, clean the valve body and replace the PC solenoid valve, if necessary.
Check the PC solenoid valve actual versus desired pressures to verify the new PC solenoid valve is responding correctly.
Refer to the Automatic Transaxle Section of the Service Manual for the proper repair procedure.
Line Pressure Check Procedure Tools Required
J 21867 Universal Pressure Gauge Set Important: Before performing a line pressure check, verify that the pressure control (PC) solenoid valve is receiving the correct electrical signal from the PCM (http://www.alldatadiy.com/alldata/AFI%7EV9277019%7EC33181%7ER0%7EOD%7EN/0/70910848/78153984/78154109/78154111/34853741/34857029/34857030/101367125). 1. Install a Scan Tool. Caution: Keep the brakes applied at all times in order to prevent unexpected vehicle motion. Personal injury may result it the vehicle moves unexpectedly. 2. Start the engine and set the parking brake. 3. Check for a stored Diagnostic Trouble Code (DTC). 4. Repair the vehicle, if necessary. 5. Check the fluid level. Refer to the Transmission Fluid Checking Procedure. 6. Check the manual linkage for proper adjustment.7. Turn the engine OFF. Remove the oil pressure test hole plug and install the J 21867. 8. Put the gear selector in PARK range and set the parking brake. 9. Start the engine and allow the engine to warm up at idle. Notice: Total test running time should not be longer than two minutes, or else transmission damage could occur.
10. Access the PC solenoid valve control test on the Scan Tool.
11. Increase the PC solenoid as shown actual current from 0.0 to 1.0 amps in 0.1 amp increments. Allow the pressure to stabilize for five seconds after each pressure change. Read the corresponding line pressure on the J 21867. 12. Refer to the Line Pressure specification table. Compare the data to the table. 13. If pressure readings differ greatly from the table, refer to Incorrect Line Pressure. 14. Remove the J 21867. 15. Apply sealant, P/N 12345382 (in Canada, P/N 10953489), to the oil pressure test hole plug. Notice: Refer to Fastener Notice in Cautions and Notices. 16. Install the oil pressure test hole plug. Tighten
Tighten the oil pressure test hole plug to 12 N.m (106 lb in).

excellent.. really appreciated... This has to be the problem but obvioulsy professional diagnosis is required.

GC